The minimum number of Flip-Flops required to construct a binary Modulo $n$ counter is ________
n flip flops can be used to make modulo 2n counter.
So according to the question the answer must be ceil(log2(n))
binary modulo n means the possible no.of states = n and mark them as 0,1,2,3,....n-1.
therefore you need to indicate n states with k flipflops
if n=2p then k=p
if n $\neq$ 2p then k= ⌈log2n⌉